Comparison of soybean-based practical diets containing 32, 36, or 40% crude protein fed to hybrid striped bass in earthen culture ponds

Three practical diets were formulated for hybrid striped bass (striped bass Morone saxatilis X white bass M. chrysops) grow out. The diets were formulated to contain 32, 36, or 40% crude protein and high levels of soybean meal and met the established or predicted essential amino acid requirements for this hybrid. All diets were extruded by a commercial feed mill. Diets were fed to fish in triplicate ponds for two growing seasons. Mean final weight, consumption, feed conversion ratio, and final standing crop were not significantly affected by the dietary crude protein concentration. Feed consumption appeared to be related to water temperature, maximum values occurring between 17 degrees C and 27 degrees C. Expenditures related to feed, labor, fingerlings, and electricity for agitation were the largest contributors to the cost of production. Based on these data, optimal dietary crude protein concentrations for hybrid striped bass grow out in earthen culture ponds do not appear to be greater than 32% when fish are fed practical diets containing high levels of soybean meal.